Thermostat.



J. M. JOHNSON.

THEEMOSTAT. APPLICATION FILED SBPT.15, 1-9 13.

. 1 1 3 126 Patented 0013.6, 191$ 2MFDOOOOOOOOOOOOOO D oeceeee ooooooooooooooo oooooooooooo WITNESSES: INVE N 'I'OR A T'I'ORNE Y.

UNITED STATES PATENT OFFICE.

JOHN H. JOHNSON, OF KANSAS CITY, KANSAS.

THERHOST LT.

To all whom it may concern:

Be it known that I, JOHN M. Jo nson, a citizen of the United States, resld at Kansas City, in the county of Wyan otte and State of Kansas, have invented certain new and useful Improvements in Thermostats, of which the following is a specification.

This invention has reference to improvements in thermostats designed for use more particularly in connection with fire alarm apparatus where the thermostats are located in places where a fire, if occurring, will cause a sufficient rise of temperature to operate.

. static element is readily screwed into or unscrewed from the ordinary incandescent electric lamp socket. Furthermore, to protect the thermostatic element there is provided an incasing member which may be readily attached to or removed from the socket-member and such incasing element while fully protective to the thermostatic element may be so formed as to freely admit air, or may be of such a character as to freely transmit heat from the surrounding atmosphere to the thermostatic element, so that a rise in temperature such as would occur in the case of a fire is quickly transmitted to the thermostatic element, and the latter res onds to the extent of causin the closure 0 the circuit at the circuit terminals carried by it, thereby establishing an electric circuit causing the chosen signal denoting fire conditions.

The invention will be best understood from a consideration of the following detailed description, taken in connection with the accompanying drawings forming a part of this specification, with the understanding,

however, that while in the drawings there is shown a practical embodiment of the invention, the structure illustrated in the drawings is susceptible of changes and modi- Speclflcation of Letters 2mm.

Application filed September 15, 1918.

Patented Oct. 6, 1914.

Serial in. 789,808.

fications so long as the salient features of the invention are retained and the result aimed at is obtained.

In the drawings Figure 1 is an elevation of a thermostat constructed in accordance with the present invention. Fig. 2 is a central longitudinal section thereof with some parts shown in elevation and the thermostatic element exaggerated in proportions to more clearly show its structure. -Fig. 3 is a view of the thermostatic element detached from the supporting socket, and also like the showing of Fig. 2 somewhat exaggerated in proportions. Fig. 1 is an end view of the socket member with the sustaining screws in section. Fig. 5 is a section on. the line 55 of Fig. 2. 4

Referring to the drawings there is shown a basic member 1 which may take the form of a ceiling rosette and is formed in insulating material, usually porcelain. The basic member 1 is formed with an extension 2 in which there is lodged a screw sleeve 3 electrically connected to a strip 4 extending to the exterior of the extension 2 where it is exposed on the basic member 1 for the reception of a binding screw 5 designed to receive an electric conductor indicated at 6. Lodged withinthe sleeve 3 so as to cover the strip 4 is a plate or disk 7 of insulating material traversed by a screw 8, which also passes through the strip 4, the latter being provided with an opening 9 for the passage of screw 8, which opening is sufficiently large to prevent electric contact between the screw 8 and the strip 4.

The basic member 1 remote from the extension 2 is formed in a recess 10 in which is lodged one end of a conducting strip 11 carried to the exterior of the basic member and there exposed for the reception of a binding screw 12 designed to receive an electric conductor indicated at 13, the screws 5 and 12 being exposed adjacent the extension 2' for accessibility. The recess 10 is closed by suitable insulating material 14 after the strip 11 has been placed therein.

The head of the screw 8 is exposed within the sleeve 3 and is substantially concentric therewith, the structure being similar to an ordinary electric lamp socket. There is also provided a thermostatic element in the form of a tube 15 terminating at one end in a bulb 16 after the manner of an ordinary thermometer tube, and the bulb and stem of the tube contains a quantity of mercury, indicated at 17.

In the drawings the tube 15 and bulb 16 are shown exaggerated in size in order that the showing maybe clear, and it will be understood that the tube 15may in size agree closely to an ordinary thermometer tube. The tube is exhausted and sealed in the usual manner andin the bulb adjacent to the tube there is sealed in one end of 'a conductor 18, while at the other end of the tube 15 there is sealed in another conductor 19. The conductor 18 dips into the mercury 17 continually, while the conductor 19 is engaged by the mercury when the latter is expanded by heat so as to reach the conductor 19, thereby completing an electric circuit of which the conductors 18 and 19 constitute terminals.

The end of tube 15 remote from the bulb 16 is carried by a block 20 of procelain or other suitable insulating material inclosed in a screw sleeve 21, and the block 20 may terminate in a conical end22 through which the conductor 19 extends centrally terminating in a small knob 23 designed to engage the exposed end of the screw 8 when the block 20 with its sleeve 21 is screwed into the socket sleeve 3, whereupon the conductor 18, which at the end remote from the bulb is secured to the sleeve 21, is brought into electric contact with the sleeve 3 and so with the conductor 6, while the conductor 19 is brought into contact with the screw 8 and therefore with the conductor 13, and if the two conductors 6 and 13 be included in a charged circuit such circuit will be completed on the expansion of the mercury 17 to connect those ends of the conductors 18 and 19 within the reach of the mercury.

The extension 2 has applied thereto a casing 24 of a size and shape to inclose the thermometer or thermostat tube 15 when its plug end is inserted in the socket, and this casing 2 1 is provided with numerous perforations 25 and may be secured to the extension 2 by a screw 26, or more than one screw if desired, the extension 2 being preferably recessed at its outer wall to receive the corresponding end of the casing, the latter being closed except at the end where applied to the extension 2; In an alarm system, particularly a fire alarm system, the thermostats are placed in any convenient position, usually at or near the ceiling of the room to be protected, and heated air or gases of combustion arising from a fire will quickly penetrate the perforated casing and reach the thermometer tube causing an expansion of the mercury sufliciently to close the circuit, and then the alarm will be caused.

The thermometer tubes are very cheaply made with sufficient accuracy for the purposes of the invention for even should the tubes vary a degree or two from accuracy, it is of no moment, since they may be arranged to close the circuit at a temperature far below that of a fire and 'yet sufficiently above any normal or ordinary temperature condition to prevent the closing of the circuit except in the event of afire, which latter event if quite distant from the thermostat will cause the latter to respond actively before the fire can gain any material headway and long before a fire would be discovered by persons not actually present in the room or compartment where the fire breaks out.

Should a fire occur it may destroy some of the thermostats even though the fire itself be put out before much damage is done, and under these circumstances thermostats are renewed with the greatest ease and at but little cost, since it is only necessary to remove the casing 2 1, unscrew the damaged thermometer tube and replace it by a new one, after which the casing 2 1 may be re placed and the device is ready for service again.

The device of the present invention has the advantage of extreme simplicity of con struction, cheapness of manufacture and reliability, as well as the facility for replacing without the necessity of readjustment or any skill whatsoever, the removal of a damaged thermostatic unit and the insertion of a new one being as readily performed as the removal of a damaged incandescent lamp bulb and the insertion of a new one.

It will be understood that the basic or socket member 1 may be readily attached to a ceiling by screws 27 which may traverse the basic member 1 which extends laterally with relation to the extension 2 at such lateral extension, so that the basic member is readily attached to a wall or other support.

What is claimed is:

1. In a thermostat, athermostatic unit comprising a thermometer tube with a bulb at one end, and a screw plugcarrying the thermometer tube at the end remote from the bulb, said screw plug having central and peripheral contact terminals and said thermometer tube having spaced electric conductors sealed therein, one conductor being sealed into the bulb adjacent the tube in contact with the liquid in the thermometer and the other being sealed in the end of the tube remote from the bulb and normally out of contact with the liquid in the thermometer and both conductors being connected to the respective contact terminals of the plug, the first mentioned conductor leading outwardly from the bulb alongside the tube to the opposite end and there fastened to the screw lug. p 2. In a thermostat, a thermostatic unit comprising a thermometer tube with a bulb at one end and a screw plug oarrying'a then.

mometer tube at the end remote from the bulb, said screw plug having central and peripheral contact terminals and said ther- 5 mometer tube having spaced electric conductors sealed therein, one conductor being sealed; into the bulb adjacent the tube in contact with liquid in the thermometer and the other being seated; into the end of the 10 tube remote from the bulb and; normally out oi contact with the iioieidi in the thermome- L s being ccnnected to respective contact terminals the ping,

cc t e 3.691559 the n L3,? De. Vilma minals of the plug in contact with those of 20 the socket, and a casing pervious to air and sha ed to inclose the thermometer tube with its ulb and embrace a portion of the socket member.

3. In a device of the class described, a 25 housing, a cap thereon, a mercury-containing tube carried by said cap Within said housing, and electric conductors extending from the exterior thereof, into andspaced apart Within said tube; substantially as de- 3 scribed.

c In testimony Whereoi Z my signature, in the presence of two Witnesses.

JOHN M. J KE? 

